1. Field of the Invention
The present invention broadly relates to analysis of surface topography of an object and, more particularly, is concerned with apparatus and method for generating a space volume-filling structured light beam array for use in non-contact surface metrology of various solid forms.
2. Description of the Prior Art
Generation of rectilinear arrays of light beams has been found useful for the analysis of surface object topography. Refer for example to U.S. Pat. No. 4,070,683 (issued to Bruce R. Altschuler and John Taboada) and U.S. Pat. No. 4,294,544 (issued to Bruce R. Altschuler, John Taboada and Martin D. Altschuler). Also, see the following articles: (1) "Rectangular Grid Fringe Pattern for Topographic Applications" (by John Taboada and Bruce R. Altschuler, Applied Optics, March 1976, Vol. 15, No. 3, pp. 597-599); (2) "Measuring Surfaces Space-Coded by a Laser-Projected Dot Matrix" (by Martin D. Altschuler, Bruce R. Altschuler and John Taboada, SPIE 1979, Vol. 182, pp. 187-191); (3) "Laser Electro-Optic System for Rapid Three-dimensional (3-D) Topographic Mensuration" (by Bruce R. Altschuler, Martin D. Altschuler and John Toboada, SPIE 1979, Vol. 182, pp. 192-196); (4) "Topographic Mapping of Oral Structures--Problems and Applications in Prosthodonitcs" (by John M. Young and Bruce R. Altschuler, SPIE 1981, Vol. 283, pp. 70-77); (5) "The Numerical Stero Camera" (by Martin D. Altschuler, Jeffery L. Postamer, Gideon Frieder, Bruce R. Altschuler and John Taboada, SPIE 1981, Vol. 283, pp. 15-25); and (6) "Laser Electro-Optic System for Rapid Three-dimensional (3-D) Topographic Mapping of Surfaces" (by Martin D. Altschuler, Bruce R. Altschuler and John Taboada, Optical Engineering, November/December 1981, Vol. 20, No. 6, pp. 953-961).
Prior methods of generating rectilinear or rectangular beam arrays have involved the interferometric combination of the front and back reflections of thin beam splitter or shearing plates, reflecting a point source of laser light. The resulting pattern although nicely arranged and collimated suffers from extensive attenuation of the working laser beam.
Consequently, there exists a need for a more efficient means of producing such a rectangular array.